HPAS 2017 Mathematics Optional Paper-1: Complete Solutions
Welcome to the comprehensive solution guide for the Himachal Pradesh Administrative Service (HPAS) 2017 Mathematics Optional Paper-1. This resource provides detailed, step-by-step solutions designed specifically for civil service aspirants to master the core mathematical concepts and methodologies required for the exam.
Whether you are revising key theorems, practicing previous year questions, or mastering advanced analytical geometry and calculus, these carefully structured solutions will help streamline your preparation. Use the index below to jump directly to specific questions and topics.
Table of Contents
- Question 1(a): Nilpotent Matrix Identity
- Question 1(b): Concavity and Convexity of a Curve
- Question 1(c): Degree and Order of Differential Equation
- Question 1(d): Irrotational Vector
- Question 2(a): Matrix Representation of Linear Transformation
- Question 2(b): Cauchy-Schwarz Inequality
- Question 3(a): Curve of Intersection with Asymptotes
- Question 3(b): Bounded Function and Riemann Integrability
- Question 4(a): Condition for Line to Touch a Circle
- Question 4(b): Sphere with Smallest Radius
- Question 5(a): Method of Variation of Parameters
- Question 5(b): Bessel’s Function Recurrence Relation
- Question 6(a): Serret-Frenet Formulas
- Question 6(b): Stokes’ Theorem Verification
- Question 7(a): Equilibrium of Five Weightless Rods
- Question 7(b): Central Axis of Equivalent Wrench
- Question 8(a): Particle Path with Equal Accelerations
- Question 8(b): Periodic Time of Elliptical Orbit
HPAS 2017 Maths Optional Paper-1 Question 1(a)
If A is a nilpotent matrix of index 2, show that A(I \pm nA) = A for any positive integer n.
Solution:
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HPAS 2017 Maths Optional Paper-1 Question 1(b)
Examine the curve x=6t^2, y=4t^3-3t for concavity and convexity.
Solution:
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HPAS 2017 Maths Optional Paper-1 Question 1(c)
Find the degree and order of the following differential equation:
\left|1+\left(\frac{dy}{dx}\right)^2\right|^{2/3} = \rho\frac{d^2y}{dx^2}Solution:
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HPAS 2017 Maths Optional Paper-1 Question 1(d)
If \vec{r} = x\mathbf{i} + y\mathbf{j} + z\mathbf{k}, then show that the vector \vec{r} is an irrotational vector.
Solution:
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HPAS 2017 Maths Optional Paper-1 Question 2(a)
Find the matrix representation of a linear transformation t on V_3(\mathbb{R}) defined as t(x,y,z)=(2y+z, x-4y, 3x) corresponding to the basis B = \{(1,0,0), (0,1,0), (0,0,1)\}.
Solution:
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HPAS 2017 Maths Optional Paper-1 Question 2(b)
State and prove the Cauchy-Schwarz inequality.
Solution:
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HPAS 2017 Maths Optional Paper-1 Question 3(a)
Find the curve on which the three points of intersection of the curve x^2y - xy^2 + xy + y^2 + x - y = 0 with its asymptotes lie.
Solution:
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HPAS 2017 Maths Optional Paper-1 Question 3(b)
Prove that a bounded function is not necessarily Riemann integrable.
Solution:
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HPAS 2017 Maths Optional Paper-1 Question 4(a)
Find the condition that the straight line \frac{l}{r} = A\cos\theta + B\sin\theta may touch the circle r = 2a\cos\theta.
Solution:
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HPAS 2017 Maths Optional Paper-1 Question 4(b)
Find the equation of a sphere which passes through the points (1, 0, 0), (0, 1, 0), and (0, 0, 1) and has the smallest possible radius.
Solution:
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HPAS 2017 Maths Optional Paper-1 Question 5(a)
Solve the following differential equation by the method of variation of parameters:
(1-x)\frac{d^2y}{dx^2} + x\frac{dy}{dx} - y = (1-x)^2Solution:
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HPAS 2017 Maths Optional Paper-1 Question 5(b)
For Bessel’s function J_n(x), show that:
2nJ_n(x) = x[J_{n-1}(x) + J_{n+1}(x)]
Solution:
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HPAS 2017 Maths Optional Paper-1 Question 6(a)
Obtain the Serret-Frenet formulas.
Solution:
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HPAS 2017 Maths Optional Paper-1 Question 6(b)
Verify Stokes’ theorem for the function \vec{F} = z\mathbf{i} + x\mathbf{j} + y\mathbf{k}, where C is the unit circle in the xy-plane bounding the hemisphere z = \sqrt{1-x^2-y^2}.
Solution:
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HPAS 2017 Maths Optional Paper-1 Question 7(a)
Five weightless rods of equal length are jointed together to form a rhombus ABCD with one diagonal BD. If a weight W is attached to C and the system is suspended from A, show that there is a thrust in BD equal to \frac{W}{\sqrt{3}}.
Solution:
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HPAS 2017 Maths Optional Paper-1 Question 7(b)
Two forces act, one along the line y=0, z=0 and the other along the line x=0, z=c. As the forces vary, show that the surface generated by the central axis of their equivalent wrench is (x^2+y^2)z = cy^2.
Solution:
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HPAS 2017 Maths Optional Paper-1 Question 8(a)
A particle moves in a curve such that its tangential and normal accelerations are equal and the angular velocity of the tangent is constant. Find the path.
Solution:
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HPAS 2017 Maths Optional Paper-1 Question 8(b)
A particle describes an ellipse under a force \frac{\mu}{(\text{distance})^2} towards a focus. If it was projected with velocity V from a point at a distance r from the center of force, show that its periodic time is
\frac{2\pi}{\sqrt{\mu}} \left[ \frac{2}{r} - \frac{V^2}{\mu} \right]^{-3/2}Solution:
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